Re: [Elecraft] ½ λ dipoles

[WILLIS COOKE via Elecraft]

Try any handbook before 1957 when transistors became available.  If you can't 
find them at the ARRL, try E-BAY as they are only available used.K5EWJ 
(original 1956 issued call sign)

  From: rick jones via Elecraft <elecraft@mailman.qth.net>
 To: "elecraft@mailman.qth.net" <elecraft@mailman.qth.net> 
 Sent: Saturday, August 6, 2016 1:00 PM
 Subject: Re: [Elecraft] ½ λ dipoles
   
Fascinating discussion. Anybody know of any noteworthy books that cover the 
subject? Especially tube transmitters and their antennas. Given my love for 
Steam trains, breadboard receivers  and Ham Radio, I sometimes think I was born 
about 50 years too late!
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Re: [Elecraft] ½ λ dipoles

[rick jones via Elecraft]

Fascinating discussion. Anybody know of any noteworthy books that cover the 
subject? Especially tube transmitters and their antennas. Given my love for 
Steam trains, breadboard receivers  and Ham Radio, I sometimes think I was born 
about 50 years too late!
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Re: [Elecraft] ½ λ dipoles

[Ron D'Eau Claire]

Egzactly Walter... that's the antenna arrangement I was thinking of back before 
DX on the 
"short waves" was discovered!

Thanks, 


73, Ron AC7AC

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Walter 
Underwood
Sent: Friday, August 5, 2016 5:23 PM
To: Elecraft Reflector
Subject: Re: [Elecraft] ½ λ dipoles

Some of the early “clothesline” antennas were a large capacity hat on a 
vertical. If the antenna has one vertical wire connected to all of the top 
wires, it is probably a capacity-loaded vertical. This Wikimedia image shows a 
top-loaded vertical.

https://commons.wikimedia.org/wiki/File:Amateur_radio_T_antenna_1912.png 
<https://commons.wikimedia.org/wiki/File:Amateur_radio_T_antenna_1912.png>

With longwave communication, a resonant antenna was not practical for most 
hams, whether horizontal or vertical. I certainly don’t have room for a 
half-wave for the 600 meter band.

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Aug 5, 2016, at 4:53 PM, Don Wilhelm <donw...@embarqmail.com> wrote:
> 
> Charlie,
> 
> A bit of history ---
> 
> Most of those ham antennas that used parallel wires were folded dipole 
> antennas - yes they were mostly 1/2 wavelength long.  The feedpoint impedance 
> for that antenna is 300 ohms.  Add a 3rd wire or a 4th and the impedance 
> increases.  So to my mind, that was an attempt to match the feedline to the 
> antenna which in early days was open wire line which for normal spacing has a 
> characteristic impedance near 600 ohms.
> By the time I became a ham, TV twinlead was common with a characteristic 
> impedance of 300 ohms.  Many ham antennas were created using that twinlead.  
> A folded dipole was made from the twinlead and fed in the center with 
> additional twinlead serving as the feedline.
> 
> With the migration to coax feedlines, those older techniques have faded from 
> memory, but those antenna *did* work just fine although many hams did not 
> really understand why.
> 
> At that time we had PA tank circuits with swinging link coils and could match 
> most any impedance.  The tuning sequence was to start with the link lightly 
> coupled to the PA inductor and then to "dip the plate" to resonance - then 
> slowly increase the coupling between the PA inductor and the antenna link to 
> increase the PA current.  That was done in an iterative manner until the 
> plate current was at the desired point.
> That process could match most any load that the antenna and feedline might 
> present to the transmitter.
> 
> Then came television.  Many ham transmitters were interfering with TV 
> reception, so transmitters became shielded devices, and the shift to coax 
> rather than open transmitters with the older parallel feedline connection 
> direct to the antenna slowly became a product of the past.  Swinging links 
> and plug in coils inside a shielded enclosure were possible, but a PITA.
> So the advent of the Pi-Network in ham transmitters was born.  It allowed 
> band switching and could match a reasonable range of antenna impedance.  The 
> shielded coax feedlines provided the chassis shield to be extended all the 
> way to the antenna feedpoint (or so the story goes, but that is not entirely 
> true).
> 
> The bottom line of what I am trying to communicate is that much of ham radio 
> antennas, transmission lines and transmitter construction changed drastically 
> in the 1950s with the advent of television and that was done primarily to 
> reduce ham interference to TV viewing (TVI).
> As an example of that effort, my first novice transmitter which I built from 
> a design in a 1955 ARRL Handbook was in a completely shielded enclosure and 
> used shielded wiring throughout with bypass capacitors at each end of the 
> shield wire.  That included all the wiring, filaments and DC power circuits 
> and anything else.  If you find a 1955 ARRL handbook it was the 75 watt 
> transmitter with a 5763 crystal oscillator and 6146 final included in that 
> book. Nostalgia urges me to again build that transmitter, but practical sense 
> says that it would be prohibitively expensive these days and some components 
> are no longer available.
> 
> 73,
> Don W3FPR
> 
> On 8/5/2016 6:41 PM, Charlie T, K3ICH wrote:
>> I'm curious as to when the concept of a ½ λ dipole became the norm?
>> 
>> In other words, the idea of the current distribution as exists on a dipole.
>> 
>> Early pictures of typical ham antennas looked more like a set of 
>> parallel clothesline wires.
>> 
>> What I gather from reading early articles,  it seemed that the more 
>> wire you had in the air, the better it would "capture" (and radiate) the 
>>

Re: [Elecraft] ½ λ dipoles

[Walter Underwood]

Some of the early “clothesline” antennas were a large capacity hat on a 
vertical. If the antenna has one vertical wire connected to all of the top 
wires, it is probably a capacity-loaded vertical. This Wikimedia image shows a 
top-loaded vertical.

https://commons.wikimedia.org/wiki/File:Amateur_radio_T_antenna_1912.png 


With longwave communication, a resonant antenna was not practical for most 
hams, whether horizontal or vertical. I certainly don’t have room for a 
half-wave for the 600 meter band.

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Aug 5, 2016, at 4:53 PM, Don Wilhelm  wrote:
> 
> Charlie,
> 
> A bit of history ---
> 
> Most of those ham antennas that used parallel wires were folded dipole 
> antennas - yes they were mostly 1/2 wavelength long.  The feedpoint impedance 
> for that antenna is 300 ohms.  Add a 3rd wire or a 4th and the impedance 
> increases.  So to my mind, that was an attempt to match the feedline to the 
> antenna which in early days was open wire line which for normal spacing has a 
> characteristic impedance near 600 ohms.
> By the time I became a ham, TV twinlead was common with a characteristic 
> impedance of 300 ohms.  Many ham antennas were created using that twinlead.  
> A folded dipole was made from the twinlead and fed in the center with 
> additional twinlead serving as the feedline.
> 
> With the migration to coax feedlines, those older techniques have faded from 
> memory, but those antenna *did* work just fine although many hams did not 
> really understand why.
> 
> At that time we had PA tank circuits with swinging link coils and could match 
> most any impedance.  The tuning sequence was to start with the link lightly 
> coupled to the PA inductor and then to "dip the plate" to resonance - then 
> slowly increase the coupling between the PA inductor and the antenna link to 
> increase the PA current.  That was done in an iterative manner until the 
> plate current was at the desired point.
> That process could match most any load that the antenna and feedline might 
> present to the transmitter.
> 
> Then came television.  Many ham transmitters were interfering with TV 
> reception, so transmitters became shielded devices, and the shift to coax 
> rather than open transmitters with the older parallel feedline connection 
> direct to the antenna slowly became a product of the past.  Swinging links 
> and plug in coils inside a shielded enclosure were possible, but a PITA.
> So the advent of the Pi-Network in ham transmitters was born.  It allowed 
> band switching and could match a reasonable range of antenna impedance.  The 
> shielded coax feedlines provided the chassis shield to be extended all the 
> way to the antenna feedpoint (or so the story goes, but that is not entirely 
> true).
> 
> The bottom line of what I am trying to communicate is that much of ham radio 
> antennas, transmission lines and transmitter construction changed drastically 
> in the 1950s with the advent of television and that was done primarily to 
> reduce ham interference to TV viewing (TVI).
> As an example of that effort, my first novice transmitter which I built from 
> a design in a 1955 ARRL Handbook was in a completely shielded enclosure and 
> used shielded wiring throughout with bypass capacitors at each end of the 
> shield wire.  That included all the wiring, filaments and DC power circuits 
> and anything else.  If you find a 1955 ARRL handbook it was the 75 watt 
> transmitter with a 5763 crystal oscillator and 6146 final included in that 
> book. Nostalgia urges me to again build that transmitter, but practical sense 
> says that it would be prohibitively expensive these days and some components 
> are no longer available.
> 
> 73,
> Don W3FPR
> 
> On 8/5/2016 6:41 PM, Charlie T, K3ICH wrote:
>> I'm curious as to when the concept of a ½ λ dipole became the norm?
>> 
>> In other words, the idea of the current distribution as exists on a dipole.
>> 
>> Early pictures of typical ham antennas looked more like a set of parallel
>> clothesline wires.
>> 
>> What I gather from reading early articles,  it seemed that the more wire you
>> had in the air, the better it would "capture" (and radiate) the signals.
>> 
>> Feel free to reply directly if you don't want to clutter the forum.
>> 
>> (k3ich at arrl dot net)
>> 
>> 
> 
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> This list hosted by: http://www.qsl.net
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Re: [Elecraft] ½ λ dipoles

[Ron D'Eau Claire]

What Don says is quite right for the 1930's, 40's and onward. I was
describing the early antennas of the teens an 20's. They have but one wire
feed with several parallel wires the last few feet to connect to the
horizontal wires. 

Once Hams moved quickly from 200 meters to 80, 40 and even the rarified high
frequency of 20 meters the antennas changed accordingly. 

Multi-wire folded dipoles were, as Don says, an easy way to match 600 ohm
open wire lines (although few Hams cared about SWR) and had the side
advantage of broadening the frequency response. 

73, Ron AC7AC

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Don
Wilhelm
Sent: Friday, August 5, 2016 4:53 PM
To: Charlie T, K3ICH; elecraft@mailman.qth.net
Subject: Re: [Elecraft] ½ λ dipoles

Charlie,

A bit of history ---

Most of those ham antennas that used parallel wires were folded dipole
antennas - yes they were mostly 1/2 wavelength long.  The feedpoint
impedance for that antenna is 300 ohms.  Add a 3rd wire or a 4th and the
impedance increases.  So to my mind, that was an attempt to match the
feedline to the antenna which in early days was open wire line which for
normal spacing has a characteristic impedance near 600 ohms.
By the time I became a ham, TV twinlead was common with a characteristic
impedance of 300 ohms.  Many ham antennas were created using that twinlead.
A folded dipole was made from the twinlead and fed in the center with
additional twinlead serving as the feedline.

With the migration to coax feedlines, those older techniques have faded from
memory, but those antenna *did* work just fine although many hams did not
really understand why.

At that time we had PA tank circuits with swinging link coils and could
match most any impedance.  The tuning sequence was to start with the link
lightly coupled to the PA inductor and then to "dip the plate" to resonance
- then slowly increase the coupling between the PA inductor and the antenna
link to increase the PA current.  That was done in an iterative manner until
the plate current was at the desired point.
That process could match most any load that the antenna and feedline might
present to the transmitter.

Then came television.  Many ham transmitters were interfering with TV
reception, so transmitters became shielded devices, and the shift to coax
rather than open transmitters with the older parallel feedline connection
direct to the antenna slowly became a product of the past.  
Swinging links and plug in coils inside a shielded enclosure were possible,
but a PITA.
So the advent of the Pi-Network in ham transmitters was born.  It allowed
band switching and could match a reasonable range of antenna impedance.  The
shielded coax feedlines provided the chassis shield to be extended all the
way to the antenna feedpoint (or so the story goes, but that is not entirely
true).

The bottom line of what I am trying to communicate is that much of ham radio
antennas, transmission lines and transmitter construction changed
drastically in the 1950s with the advent of television and that was done
primarily to reduce ham interference to TV viewing (TVI).
As an example of that effort, my first novice transmitter which I built from
a design in a 1955 ARRL Handbook was in a completely shielded enclosure and
used shielded wiring throughout with bypass capacitors at each end of the
shield wire.  That included all the wiring, filaments and DC power circuits
and anything else.  If you find a 1955 ARRL handbook it was the 75 watt
transmitter with a 5763 crystal oscillator and 6146 final included in that
book. Nostalgia urges me to again build that transmitter, but practical
sense says that it would be prohibitively expensive these days and some
components are no longer available.

73,
Don W3FPR

On 8/5/2016 6:41 PM, Charlie T, K3ICH wrote:
> I'm curious as to when the concept of a ½ λ dipole became the norm?
>
> In other words, the idea of the current distribution as exists on a
dipole.
>
> Early pictures of typical ham antennas looked more like a set of 
> parallel clothesline wires.
>
> What I gather from reading early articles,  it seemed that the more 
> wire you had in the air, the better it would "capture" (and radiate) the
signals.
>
> Feel free to reply directly if you don't want to clutter the forum.
>
> (k3ich at arrl dot net)
>
>

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Re: [Elecraft] ½ λ dipoles

[Don Wilhelm]

Charlie,

A bit of history ---

Most of those ham antennas that used parallel wires were folded dipole 
antennas - yes they were mostly 1/2 wavelength long.  The feedpoint 
impedance for that antenna is 300 ohms.  Add a 3rd wire or a 4th and the 
impedance increases.  So to my mind, that was an attempt to match the 
feedline to the antenna which in early days was open wire line which for 
normal spacing has a characteristic impedance near 600 ohms.
By the time I became a ham, TV twinlead was common with a characteristic 
impedance of 300 ohms.  Many ham antennas were created using that 
twinlead.  A folded dipole was made from the twinlead and fed in the 
center with additional twinlead serving as the feedline.


With the migration to coax feedlines, those older techniques have faded 
from memory, but those antenna *did* work just fine although many hams 
did not really understand why.


At that time we had PA tank circuits with swinging link coils and could 
match most any impedance.  The tuning sequence was to start with the 
link lightly coupled to the PA inductor and then to "dip the plate" to 
resonance - then slowly increase the coupling between the PA inductor 
and the antenna link to increase the PA current.  That was done in an 
iterative manner until the plate current was at the desired point.
That process could match most any load that the antenna and feedline 
might present to the transmitter.


Then came television.  Many ham transmitters were interfering with TV 
reception, so transmitters became shielded devices, and the shift to 
coax rather than open transmitters with the older parallel feedline 
connection direct to the antenna slowly became a product of the past.  
Swinging links and plug in coils inside a shielded enclosure were 
possible, but a PITA.
So the advent of the Pi-Network in ham transmitters was born.  It 
allowed band switching and could match a reasonable range of antenna 
impedance.  The shielded coax feedlines provided the chassis shield to 
be extended all the way to the antenna feedpoint (or so the story goes, 
but that is not entirely true).


The bottom line of what I am trying to communicate is that much of ham 
radio antennas, transmission lines and transmitter construction changed 
drastically in the 1950s with the advent of television and that was done 
primarily to reduce ham interference to TV viewing (TVI).
As an example of that effort, my first novice transmitter which I built 
from a design in a 1955 ARRL Handbook was in a completely shielded 
enclosure and used shielded wiring throughout with bypass capacitors at 
each end of the shield wire.  That included all the wiring, filaments 
and DC power circuits and anything else.  If you find a 1955 ARRL 
handbook it was the 75 watt transmitter with a 5763 crystal oscillator 
and 6146 final included in that book. Nostalgia urges me to again build 
that transmitter, but practical sense says that it would be 
prohibitively expensive these days and some components are no longer 
available.


73,
Don W3FPR

On 8/5/2016 6:41 PM, Charlie T, K3ICH wrote:

I'm curious as to when the concept of a ½ λ dipole became the norm?

In other words, the idea of the current distribution as exists on a dipole.

Early pictures of typical ham antennas looked more like a set of parallel
clothesline wires.

What I gather from reading early articles,  it seemed that the more wire you
had in the air, the better it would "capture" (and radiate) the signals.

Feel free to reply directly if you don't want to clutter the forum.

(k3ich at arrl dot net)




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Re: [Elecraft] ½ λ dipoles

[Ron D'Eau Claire]

A 1/2 wave radiator (a.k.a. "dipole") is the shortest 'self resonant'
radiator independent of the ground. By self-resonant I mean that it has zero
reactance. 

Heinrich Hertz used a dipole in his demonstrations of electromagnetic waves
in the form of a 1/2 wave pipe bent nearly in a circle so the ends nearly
touched each other. When an identical loop nearby was excited, tiny sparks
would jump across the ends of the second loop even though there was no
mechanical connection. 

Marconi pioneered the grounded monopole which needed to be only half as
long.  

The idea of "resonance" (called "synchronicity" then) was just becoming
recognized in Marconi's time. Back then the antenna set the frequency of the
transmitter, so the antenna had to be designed to produce the desired
wavelength of signal.

Longer wavelengths were thought to produce DX. But longer wavelengths
require HUGE antennas of several hundred meters in length, even a monopole
worked against "ground". So "top loading" became very popular. 

That's where you see the multi-wire arrangements of early Ham stations. The
"antenna" was actually the wire leading up to the parallel wires strung up
high. The parallel wires provided the needed capacitance to ground to lower
the frequency (increase the wavelength). 

Since until the late 1920's most Hams clustered as close to 200 meters as
possible (the longest wavelength Hams were allowed in  the USA) in the
belief that longer wavelengths were needed for longer distances, such
antennas were very popular.

About then the "short waves" were discovered and everything changed!

73, Ron AC7AC 

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of
Charlie T, K3ICH
Sent: Friday, August 5, 2016 3:42 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] ½ λ dipoles

I'm curious as to when the concept of a ½ λ dipole became the norm?

In other words, the idea of the current distribution as exists on a dipole.

Early pictures of typical ham antennas looked more like a set of parallel
clothesline wires.

What I gather from reading early articles,  it seemed that the more wire you
had in the air, the better it would "capture" (and radiate) the signals.

Feel free to reply directly if you don't want to clutter the forum.

(k3ich at arrl dot net)

73, Charlie k3ICH



-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Phil
Wheeler
Sent: Friday, August 05, 2016 10:58 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] OT:. G5RV's

Alas, the poor G5RV.  Now that its been flogged to death, maybe we need a
new target -- say the Windom?

Phil W7OX

On 8/4/16 10:22 PM, Wes Stewart wrote:
> The tuner loss also depends on how it is adjusted. For example the 
> very popular high-pass Tee with three adjustable elements has an 
> infinite number of possible combinations that will effect a match on 
> the same load Z.  One of them is the lowest loss solution, all of the 
> others aren't.
>
> As I said earlier, in a letter to Dean Straw dated February 2, 1994 I 
> offered an example where the SPC tuner, then current in the handbooks, 
> could be used to match an impedance of 4.34 +j46 to 50 ohm. (I forget 
> where this came from but it was a real possibility)  I assumed Qc =
> 1000 and Ql = 300 (generous). I used Touchstone to calculate the 
> minimum loss and maximum loss solutions The best case was 1.6 dB and 
> the worst case was 7.8 dB.
>
> With lower Q components, Qc = 500, Ql =200, the losses were 2.4 to 9.5 
> dB!
>
> Wes  N7WS
>
>
>  On 8/4/2016 2:00 PM, Alan Bloom wrote:
>> > It's a pity that too many newcomers, as well
>> as many oldsters, are
>> > enamored by this piece of wire.
>>
>> The G4RV is definitely a compromise antenna.  
>> However its advantage is that is has low-enough SWR to be easily 
>> matched by most tuners on a number of bands.
>>
>> > ... the horrific losses that could be
>> incurred even
>> > with high quality tuners,
>>
>> It's true that tuner losses are the
>> manufacturers' dirty little secret. Loss is rarely specified, partly 
>> because it can be pretty bad, and partly because it is hard to 
>> measure, but also because it is not constant - it depends on the 
>> particular impedance being matched.
>>
>> One exception is the old Drake tuners.  Their Pi-L topology makes the 
>> loss almost independent of the load impedance.  If you can get it to 
>> match, you know that almost all the power is going into the feed 
>> line. For example, the
>> MN-2700 that I designed when I was at Drake was specified at 0.5 dB 
>> maximum insertion loss and I did a lot of testing and tweaking to 
>> achieve that on all bands.

Re: [Elecraft] ½ λ dipoles

[riese-k3djc]

early on the antenna would help define the operating frequency
spark made RF everywhere and the tank and antenna coupled
the RF to the operating frequency

Bob K3DJC




On Fri, 5 Aug 2016 18:41:57 -0400 "Charlie T, K3ICH" 
writes:
> I'm curious as to when the concept of a ½ λ dipole became the norm?
> 
> In other words, the idea of the current distribution as exists on a 
> dipole.
> 
> Early pictures of typical ham antennas looked more like a set of 
> parallel
> clothesline wires.
> 
> What I gather from reading early articles,  it seemed that the more 
> wire you
> had in the air, the better it would "capture" (and radiate) the 
> signals.
> 
> Feel free to reply directly if you don't want to clutter the forum.
> 
> (k3ich at arrl dot net)
> 
> 73, Charlie k3ICH
> 
> 
> 
> -Original Message-
> From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf 
> Of Phil
> Wheeler
> Sent: Friday, August 05, 2016 10:58 AM
> To: elecraft@mailman.qth.net
> Subject: Re: [Elecraft] OT:. G5RV's
> 
> Alas, the poor G5RV.  Now that its been flogged to death, maybe we 
> need a
> new target -- say the Windom?
> 
> Phil W7OX
> 
> On 8/4/16 10:22 PM, Wes Stewart wrote:
> > The tuner loss also depends on how it is adjusted. For example the 
> 
> > very popular high-pass Tee with three adjustable elements has an 
> > infinite number of possible combinations that will effect a match 
> on 
> > the same load Z.  One of them is the lowest loss solution, all of 
> the 
> > others aren't.
> >
> > As I said earlier, in a letter to Dean Straw dated February 2, 
> 1994 I 
> > offered an example where the SPC tuner, then current in the 
> handbooks, 
> > could be used to match an impedance of 4.34 +j46 to 50 ohm. (I 
> forget 
> > where this came from but it was a real possibility)  I assumed Qc 
> = 
> > 1000 and Ql = 300 (generous). I used Touchstone to calculate the 
> > minimum loss and maximum loss solutions The best case was 1.6 dB 
> and 
> > the worst case was 7.8 dB.
> >
> > With lower Q components, Qc = 500, Ql =200, the losses were 2.4 to 
> 9.5 
> > dB!
> >
> > Wes  N7WS
> >
> >
> >  On 8/4/2016 2:00 PM, Alan Bloom wrote:
> >> > It's a pity that too many newcomers, as well
> >> as many oldsters, are
> >> > enamored by this piece of wire.
> >>
> >> The G4RV is definitely a compromise antenna.  
> >> However its advantage is that is has low-enough SWR to be easily 
> >> matched by most tuners on a number of bands.
> >>
> >> > ... the horrific losses that could be
> >> incurred even
> >> > with high quality tuners,
> >>
> >> It's true that tuner losses are the
> >> manufacturers' dirty little secret. Loss is rarely specified, 
> partly 
> >> because it can be pretty bad, and partly because it is hard to 
> >> measure, but also because it is not constant - it depends on the 
> >> particular impedance being matched.
> >>
> >> One exception is the old Drake tuners.  Their Pi-L topology makes 
> the 
> >> loss almost independent of the load impedance.  If you can get it 
> to 
> >> match, you know that almost all the power is going into the feed 
> >> line. For example, the
> >> MN-2700 that I designed when I was at Drake was specified at 0.5 
> dB 
> >> maximum insertion loss and I did a lot of testing and tweaking to 
> 
> >> achieve that on all bands.
> >>
> >> Alan N1AL
> 
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Re: [Elecraft] ½ λ dipoles

[Charlie T, K3ICH]

I'm curious as to when the concept of a ½ λ dipole became the norm?

In other words, the idea of the current distribution as exists on a dipole.

Early pictures of typical ham antennas looked more like a set of parallel
clothesline wires.

What I gather from reading early articles,  it seemed that the more wire you
had in the air, the better it would "capture" (and radiate) the signals.

Feel free to reply directly if you don't want to clutter the forum.

(k3ich at arrl dot net)

73, Charlie k3ICH



-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Phil
Wheeler
Sent: Friday, August 05, 2016 10:58 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] OT:. G5RV's

Alas, the poor G5RV.  Now that its been flogged to death, maybe we need a
new target -- say the Windom?

Phil W7OX

On 8/4/16 10:22 PM, Wes Stewart wrote:
> The tuner loss also depends on how it is adjusted. For example the 
> very popular high-pass Tee with three adjustable elements has an 
> infinite number of possible combinations that will effect a match on 
> the same load Z.  One of them is the lowest loss solution, all of the 
> others aren't.
>
> As I said earlier, in a letter to Dean Straw dated February 2, 1994 I 
> offered an example where the SPC tuner, then current in the handbooks, 
> could be used to match an impedance of 4.34 +j46 to 50 ohm. (I forget 
> where this came from but it was a real possibility)  I assumed Qc = 
> 1000 and Ql = 300 (generous). I used Touchstone to calculate the 
> minimum loss and maximum loss solutions The best case was 1.6 dB and 
> the worst case was 7.8 dB.
>
> With lower Q components, Qc = 500, Ql =200, the losses were 2.4 to 9.5 
> dB!
>
> Wes  N7WS
>
>
>  On 8/4/2016 2:00 PM, Alan Bloom wrote:
>> > It's a pity that too many newcomers, as well
>> as many oldsters, are
>> > enamored by this piece of wire.
>>
>> The G4RV is definitely a compromise antenna.  
>> However its advantage is that is has low-enough SWR to be easily 
>> matched by most tuners on a number of bands.
>>
>> > ... the horrific losses that could be
>> incurred even
>> > with high quality tuners,
>>
>> It's true that tuner losses are the
>> manufacturers' dirty little secret. Loss is rarely specified, partly 
>> because it can be pretty bad, and partly because it is hard to 
>> measure, but also because it is not constant - it depends on the 
>> particular impedance being matched.
>>
>> One exception is the old Drake tuners.  Their Pi-L topology makes the 
>> loss almost independent of the load impedance.  If you can get it to 
>> match, you know that almost all the power is going into the feed 
>> line. For example, the
>> MN-2700 that I designed when I was at Drake was specified at 0.5 dB 
>> maximum insertion loss and I did a lot of testing and tweaking to 
>> achieve that on all bands.
>>
>> Alan N1AL

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